1. Field of the Invention
The present invention pertains to a friction clutch, especially to a multi-disk clutch or to a clutch disk for a friction clutch of this type.
2. Description of the Related Art
U.S. Pat. No. 5,908,100 describes a clutch disk which can be used in a multi-disk clutch. The clutch disk has an essentially flat central disk element, in the radially outer area of which radially outward-projecting friction lining carrier sections are formed as integral parts. Cover disk elements, which are or can be brought by a plurality of damper springs into torque-transmitting connection with the central disk element, are provided on both sides of the central disk element. The cover disk elements are rigidly connected radially on the inside to a hub area or carry this hub area as an integral part of themselves and thus, by a nonrotatable connection to a power takeoff element such as the input shaft to a transmission, transmit the torque which is to be transmitted by a clutch disk of this type.
A problem with clutch disks of this type is that, when they are to be integrated into a friction clutch, the space available for their installation is comparatively small. This problem becomes even more acute when the clutch is a multi-disk clutch, in which several of these types of clutch disks are arranged in a row. To accommodate these design conditions, it is known, for example, that, for at least one of the clutch disks, the friction surfaces or the friction linings carrying these friction surfaces can be provided not on the central disk element but rather on a cover disk element, so that an axial offset is present with respect to the central disk element or to the area in which the central disk element interacts with the damper elements. This means, however, that it is not the cover disk elements but rather the central disk element which must be connected to a hub area or must have a hub area of this kind. A design of this type could lead to the use of clutch disks of completely different design in one and the same friction clutch.
It is the object of the present invention to provide a friction clutch or a clutch disk for a friction clutch which makes it easy to adapt the design to various conditions within the friction clutch.
According to a first aspect, this task is accomplished by a friction clutch, especially by a multi-disk clutch, comprising at least one clutch disk, which is designed with a hub area which can be connected nonrotatably to a power takeoff element and with a friction surface area which can be clamped between opposing friction surfaces. The at least one clutch disk has a torsional vibration damper arrangement comprising two cover disk elements connected to the hub area for rotation in common and a central disk element connected to the friction surface area for rotation in common, which central disk element is in or can be brought into torque-transmitting connection with the cover disk elements by way of a damper element arrangement. The central disk element has a damper element interaction area and, radially outside the damper element interaction area, a friction surface carrier area, which is offset in the direction of an axis of rotation with respect to the damper element interaction area.
By providing an axial offset between the area of the central disk element which cooperates with the damper element arrangement and the area on which the central disk element carries or is connected to friction surfaces or friction linings, it guaranteed that the design can be adapted to various conditions in the friction clutch, and it is equally ensured that the forces are introduced into the center of the torsional vibration damper arrangement via the central disk element.
It can be provided, for example, that the central disk element has an essentially cylindrical section radially outside the damper element interaction area, on which section the friction surface carrier area is provided. By providing a cylindrical section, it becomes easy to adjust the length of the central disk element in the area where it carries the friction surface carrier, and thus an even better adaptability to various design conditions is afforded. For strength reasons, it is preferable for the cylindrical section to extend continuously around the axis of rotation in the circumferential direction. Of course, it is also possible to design the essentially cylindrical section with interruptions in the circumferential direction by providing several axially projecting sections.
It is also possible in the friction clutch according to the invention for the cylindrical section to be designed as an integral part of the damper element interaction area. For example, the central disk element can be shaped from a stock blank, preferably of sheet or plate.
To attach the friction lining carrier to the central disk element, it is possible in a design variant for the cylindrical section to have an outer circumferential connecting surface for the attachment of at least one friction lining carrier, preferably by welding, to the central disk element. So that it is possible here to provide a very precisely machined surface for the attachment of the friction lining carrier, it is proposed that the outer circumferential connecting surface be formed by machining down at least certain areas of the cylindrical section.
For the friction clutch according to the invention, the machining work can be minimized by providing the outer circumferential connecting surface of the cylindrical section only in the axial area where the friction lining carrier is to be connected to it.
As an alternative, however, it is also possible for the outer circumferential connecting surface to be provided over essentially the entire axial length of the cylindrical section. This design variant makes it possible, when adapting the disk to various basic designs of a friction clutch, for the friction lining carrier to be provided in any desired position in the axial direction on the cylindrical section. This is especially advantageous in cases where the friction clutch is a multi-disk clutch, because then the torsional vibration damper arrangements used for the various clutch disks can be essentially identical.
In an alternative design, it is also possible for the cylindrical section to have a connecting end surface for the attachment, preferably by welding, of at least one friction lining carrier to the central disk element.
As already explained, the friction clutch according to the invention can have at least two clutch disks; that is, it can be designed as a multi-disk clutch.
In such cases, it is then advantageous for the friction surface carrier areas for at least two of the clutch disks to have different offsets in the direction of the axis of rotation with respect to the associated damper element interaction areas. Especially when use is made of the previously mentioned identical torsional vibration damper arrangements for each of the various clutch disks, it is advantageous for the friction surface carrier area for at least one clutch disk to be a certain axial distance away from the axial end of the cylindrical section of the associated central disk element. In this way, different clutch disks can be provided with different axial offsets.
Because of the possibility of adapting the friction clutch according to the invention to various sets of design conditions through the variability of the axial positioning of the friction lining carrier on the central disk element or on the cylindrical section of that element, it is possible, in the case of at least two clutch disks, to use the same shaping tool to produce the central disk elements from the stock blanks. This, too, decreases the cost of production and especially the inventory costs.
According to another aspect of the invention, the task cited above is accomplished by a clutch disk which can be used in a previously described friction clutch. The hub area of this clutch disk is designed for nonrotatable connection to a power takeoff element, and the friction surface area of the disk can be clamped between two opposing friction surfaces. The clutch disk has a torsional vibration damper arrangement comprising two cover disk elements connected to the hub area for rotation in common and a central disk element connected to the friction surface area for rotation in common. The central disk element is or can be brought into torque-transmitting connecting with the cover disk elements by way of a damper element arrangement, and has a damper element interaction area. Radially outside the damper element interaction area is a friction surface carrier area, which is offset with respect to the damper element interaction area in the direction of an axis of rotation.
Of course, this clutch disk can be designed with the features specific to clutch disks described above.
The present invention is described in detail below with reference to the attached drawings, which illustrate preferred embodiments.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.